Possible bug?

There seem to exist a bug regarding party membership. My Polls Report predicts I would get 91 % of the vote, yet my party has 0 members, The other party has 996455 (1.30 %). My membership dropped in just one ore two turns and when looking at different voter groups, there is no sign of membership changes.
I am running version 1.16 and this is the second time this has happened.
Any thoughts?

It could be that voter cynicism (based on stuff like cutting taxes before elections or raising them afterwards) has risen to a point where nobody wants to be in the party. They may well still vote for you, because there approval of you is over 50%, but voter approval has to be VERY high for them to join your party. Over time, voters expectations also rise, and thus they are less likely to stay in the governing party.
It sounds like you are keeping everyone fairly happy, rather than a few people very happy.

This is a definite bug. One turn I had millions of members and more than any other party. I click next turn, and suddenly have 0. This can’t possibly be a game mechanic - every single member of my party wouldn’t just suddenly quit.

I just had the same thing happen to me.

http://img261.imageshack.us/img261/3094/democracycapia2.jpg

On the turn before, I had 6% of the population in my party.

I doubt this is a game mechanic.

I will investigate further

Ok I think I know what’s going on.

Basically party members will quit the party if their opinion of you drops below VOTER_PLAYER_DECREASE_SYMPATHY_BELOW (0.85). and stays that low for a while.
This can be reduced by this:

MANIFESTO_BROKEN_PENALTY = 0.2
COMPLACENCY_MAX = 0.33

Now if you have opinion of 100%, obviously if those two combine it gets to 0.47.
The thing is, complacency wont likely get that high, so they can still have high enough opinion to vote for you, but low enough to leave the party.

so far so good, but why would it suddenly drop?

I think its because the broken manifesto penalty only kicks in if there are less than 10 months to the election. So at that point, suddenly everyone remembers the election pledges from last time, and gets upset. Then, however long it takes for their resentment to accumulate goes by, and they suddenly quit the party together.
Basically everyone reassesses your manifesto commitments on the same day.
Does this explain the phenomena?

I’m going to reduce complacency in the full version of the game because this seems a bit too strong right now